1. Field of the Invention
The present invention relates to an electric vehicle propulsion system. More particularly, this invention relates to systems for controlling propulsion of electric vehicles and to fail safe systems for communicating between digital and analog sensors or other instrumentation in electric vehicles and the motor used to generate power for vehicle propulsion.
2. Description of the Related Art
For an electric vehicle to be commercially viable, its cost and performance should be competitive with that of its gasoline-powered counterparts. Moreover, for the components of an electric vehicle, or any vehicle, to be competitively priced, they must be interchangeable among different vehicle platforms. Interchangeable components can be mass produced and marketed at low costs in comparison to components specially manufactured for a single or a small number of vehicle platforms.
In the past, manufacturers have focused on a number of issues concerning the manufacture of electric vehicles, most of which concerned the propulsion system and methods of emulating the propulsion system on vehicles powered by combustion engines. They failed to address issues such as portability of the components used in electric vehicles, and particularly, the components used in the propulsion system of electric vehicles.
Because electric vehicles do not rely on combustion engines, but rather use batteries and electric motors for power, the components of a controller for the batteries and electric motors are suitable for interchangeability among different vehicle platforms. In the past, however, little attention was paid to the portability and interchangeability of these components.
Furthermore, little attention has been paid to development of controllers for propulsion systems of electric vehicles that incorporate simple interfaces to provide flexibility in using the controllers on different vehicle platforms with minimum modifications to the system hardware and software.